Aeronautical surfaces, in particular the surfaces lifting an aircraft during the flight thereof, are influenced in their behaviour by the physical characteristics of the air in contact with the aforementioned surface. One of the physical characteristics of greater importance is the angle of attack.
In the aeronautical field the angle of attack is the angle formed by the geometric chord of the cross-section of an aerodynamic surface with respect to the direction of the incident air. The angle of attack is a parameter decisively influencing the capacity to generate lift of the aforementioned aerodynamic surface. In general on increasing the angle of attack the lift of the surface increases until a certain point at which lift decreases sharply, a phenomenon known as stalling.
As a consequence it is of great importance in the aerodynamic field, and particularly during the phase of development and/or design, to measure the actual angle of attack of the stream of air incident upon an aerodynamic surface, in particular on a lifting surface such as wings, stabilisers and others, to be able to certify aerodynamic models realised beforehand by numerical methods and/or tunnel tests.
In this respect it becomes necessary to install on aerodynamic surfaces, and in particular on surfaces lifting an aircraft, a device to support probes to measure the angle of attack (also known as angle of incidence). By virtue of this device probes may realise the measurement of the angle of attack such that they are undisturbed by the lifting surface whereon they are disposed. Moreover the aforementioned probes require to be installed and calibrated on the foregoing device, utilising as reference independent elements of the aircraft to obviate the various tolerances which may accumulate on the different surfaces.
Devices to measure the angle of attack are known, for example from the documents U.S. Pat. No. 4,230,290, U.S. Pat. No. 2,237,306 and U.S. Pat. No. 2,855,779, in particular probes to measure the angle of attack of an aerodynamic surface, together with methods for designing such devices. The measurement probes of these documents are disturbed by the stream incident on the aerodynamic surface as a result of which they do not provide a real measurement of the angle of attack. Furthermore the calibration of these probes is not realised in an appropriate and reliable manner. Moreover the foregoing documents describe probes to measure the angle of attack of an aerodynamic surface; however they are not orientated toward a support device for the probes in compliance with the aforesaid requirements.
The present invention is orientated toward the achievement of the aforementioned objectives.